【作者】 李清晓；

【导师】 颜培实； 李忠平；

【作者基本信息】 南京农业大学 ， 动物营养与饲料科学， 2005， 硕士

【摘要】 本研究包括体外试验和体内试验两部分。体外试验采用胃蛋白酶-胰酶两步法测定豆粕的养分消化率;体内试验选用肉仔鸡作为试验动物,就豆粕的粉碎粒度对玉米豆粕日粮养分利用率及肉鸡生产性能的影响进行评定。 体外试验包括豆粕粉碎粒度及豆粕养分消化率的测定。采用十五层筛法对未粉碎(原样)豆粕和过3.0mm、2.0mm、1.2mm及0.8mm孔径粉碎机筛片的豆粕进行对数几何平均粒度的测定,结果得到相应的几何粒度:2565μm、529μm、449μm、334μm和210μm,锤片粉碎机筛孔直径与对数几何平均粒度之间存在显著正相关。模拟鸡消化道内环境的温度、pH,采用胃蛋白酶-胰酶两步法对5种粒度的豆粕分别进行体外消化。结果表明:在40℃,最适胃蛋白酶浓度(75mg/ml)和最适胰酶浓度(110mg/ml)条件下,豆粕的养分消化率随着粉碎粒度的减小而增加,粒度≤449μm组豆粕的粗蛋白、必需氨基酸和干物质的消化率显著高于其他粒度组(p<0.05)。 动物试验选用656羽0日龄AA肉仔鸡,随机分为4个组,每组4个重复,每个重复41羽鸡,进行了为期42d的饲养试验;并于饲养试验结束后,从各处理组中分别选取5只公鸡,共20只,采用全收粪法进行代谢试验,考察日粮中不同粉碎粒度豆粕对肉鸡生产性能和消化机能的影响。结果表明:(1)在饲养试验前期,豆粕粉碎粒度对肉鸡生产性能无显著影响(p>0.05);在饲养试验后期及全期,粒度≤449μm组的肉鸡的生产性能略优于其他组,且334μm组的饲料转化率较好(p<0.05)。(2)不同粉碎粒度豆粕的体内养分消化率差异较显著,449μm组日粮的能量代谢率,粗蛋白、干物质和大多数必需氨基酸的消化率均显著高于529μm和210μm组(p<0.05)。(3)豆粕粉碎粒度对42日龄肉鸡的腺胃重量,十二指肠、空肠、回肠等消化器官的相对重量和相对长度等指标无显著影响(p>0.05),210μm组肉鸡的肌胃相对重量大于其他各组,且与334μm组差异显著(p<0.05)。(4)449μm组的肉鸡空肠内容物的总蛋白水解酶活性相对最高,分别比529μm、334μm和210μm组分别提高了6.72%、6.26%和10.68%(p<0.05)。更多还原

【Abstract】 The effect of grinding particles sizes of soybean meal on the nutrient utilization of corn-soybean meal diets in broilers was studied by in vitro and in vivo methods.The grinding particle sizes and nutrition utilization of soybean meal were measured in vitro digestion trial. The particle sizes of soybean meal ungrinded and filtrated through 3.0mm, 2.0mm, 1.2mm and 0.8mm mesh sizes were determined by the fifteenth-sieve method, obtaining corresponding particle sizes of 2565μm, 529μm, 449μm, 334μm and 210μm. The average geometric particle sizes were significantly positive correlated with the grinding mesh sizes of hammer mill. Simulating the temperature and pH of the digestive tract in broiler, the five sizes soybean meals were digested in vitro adopting pepsin-trypsin method. The results showed: under the condition of 40℃, optimum pepsin concentration (75mg/ml) and trypsin thickness (110mg/ml), the digestibility of nutrition of soybean meal increased with the reducing of grinding particle sizes. The digestibility of crude protein, essential amino acids and dry matter of 449μm and below 449μm groups were significant higher than 2565μm, 529μm treatments (p<0.05).656 0-day-old AA broilers were randomly in vivo allotted to 4 dietary groups and replicated 4 times, which had 41 broilers, to carry out a 42-day feeding trial. At 42 days, one broiler was selected out from each duplicate of all treatments to study the effects of grinding particle sizes of the dietary soybean meal on the performance and digestion function of broilers by means of collection full excrements analysis method. The results showed: (l)In the starter phase there was no effect of soybean meal’s particle sizes on the broilers performance (p>0.05). In the finishing phase and whole feeding period, the broilers performance of groups with 449μm and below 449μm were slightly superior to other treatments (p<0.05). (2)The digestibility of nutrition in vivo of different particle sizes soybean meal had more significant difference, the metabolizability of energy, the digestibilities of crude protein, dry matter and essential amino acids of 449μm dietary group were higher than 529μm and 210μm significantly (p<0.05), but didn’t have difference to 334μm. (3)There were no effects of grinding particle sizes on the weight of proventriculus, the relative weight and length of duodenum, jejunum and ileum of42-day-old broilers (p>0.05). The gizzard relative weight of 210μm was higher than other groups, and was significantly differred with 334μm treatment (p<0.05). (4)Compared with 529μm, 334μm and 210μm treatments, the total protease activities in the jejunal contents of broilers of 449μm group was increased by 6.72%, 6.26% and 10.68%, respectively (p<0.05).更多还原